1. Technical Field
The present invention relates to an X-ray imaging apparatus and an operating method thereof. More particularly, the present invention relates to an X-ray imaging apparatus capable of photographing an X-ray image without loss of X-ray radiation even without an additional device for sharing a synchronizing signal with an X-ray generator, and a method of operating the same.
2. Description of the Related Art
Generally, an X-ray diagnosis system is constituted by an X-ray generator which generates X-rays and irradiates an object with the X-rays, and an X-ray imaging apparatus for photographing an X-ray image of the object.
In such an X-ray diagnosis system, the X-ray imaging apparatus sequentially perform a flush operation for eliminating dark current from an image sensor in each line, an exposure operation for absorbing X-rays radiated from the X-ray generator, and a read-out operation for allowing the X-ray imaging apparatus to read charges generated by X-ray radiation and to output image data.
Here, in response to an exposure request signal from the X-ray generator during a flush operation, the X-ray imaging apparatus completes the flush operation throughout an overall area and performs an exposure operation by sending an exposure preparation completion signal, which informs the X-ray generator of completion of preparation for exposure operation.
Such a trigger manner by handshaking a state signal between the X-ray generator and the X-ray imaging apparatus is referred to as an active line trigger manner.
For an active line trigger type X-ray generator, the X-ray imaging apparatus can complete the flush operation for a duration between a time point of receiving an exposure request signal and a time point of sending an exposure preparation completion signal, thereby providing high quality image data.
However, when using a passive line trigger type X-ray generator which radiates X-rays by sending only an exposure request signal to the X-ray imaging apparatus, or a non-line trigger type X-ray generator which radiates X-rays without sending an exposure request signal to the X-ray imaging apparatus, loss of X-rays occurs due to time consumption upon changeover from the flush operation of the X-ray imaging apparatus to the exposure operation thereof, thereby making it difficult to obtain high quality image data.
Further, when the X-ray imaging apparatus performs the exposure operation without completing the flush operation for lines in some areas in order to reduce loss of X-rays, there is a problem of deterioration in image data in each line.
Meanwhile, the X-ray imaging apparatus generally adopts a progressive flush method, in which the flush operation is continuously carried out from the first line to the last line at a gate stage in an image detector.
However, since the progressive flush method requires a relatively long time until the flush operation is completed, large amounts of X-rays can be lost when the progressive flush operation is applied to the passive line trigger type or the non-line trigger type.